From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CC5BF2CCC6; Sat, 19 Sep 2026 20:29:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789849773; cv=none; b=cW5CXSgGIGRB6pEs+CrHtK6m5l94JraxOCncdrrJJp7zeCsjXdxIWsdqnKmIMrqoCZuzJcMdgrOsago2fC2A6ZDQ24RR7b3hiktsI6WBjag7MPtT8hm46Qar5xAY0Koa0SQDvdkUoabe6UYEPgGPiMsvc/KcR5mDAJbp3EAePwc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789849773; c=relaxed/simple; bh=wIQkGPrpNhIPeBtQ1N8sfhUKxd0h+65q0mrZReynOIY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=dFj2WOR9GoIicMAeWuRl2UHrxiGiF0PfCbX9WvHhQjQRLMJldE2kr4EhasfrczzA/FstclQm5A2VqUS9xKMithElzxHcTk9tYOWjdS4JRsoS8IS02CHziH2uZOPT4BVYVyVMHwLsuXG+cWdGZQ8fo9VVdUzhmJXo0Pm4XMCKUzA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ToFvT9JD; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ToFvT9JD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D2F711F000FF; Sat, 19 Sep 2026 20:29:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789849772; bh=19uWkkjWrdCxybP4+/+w8dWq8MXHmX5ZLbJ98WpydaY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ToFvT9JDiSGqdaYHvWSz+AFBC0Ya8da+FxkaSQFQJnqC/pP4FpRKgtvf2hyM89k0J 1cpRBVD4NYoFMoyUb0VlAxcCCc9a/hbSfO4obAF//syU+m0hy3fE71J0sGfXMyYBb/ HY5PpX/7t+vbDZ7MSz4YkD7ZQ+bCcs8WElJKcU6kfBjaqPqizJpyzy0NaUr2WTzqwZ 59/K/NYT4K0aMq+KiQQjG0AX1lSvHu1He4Kg7vF4J2us2RShq7w7nP/cLhNjKLrJHY /wasNzjtd80ZZ+OnT5/u2UZQyyc6WDVvcCG54K76n8heTNfD7Un0JUQRC8LFxJ1v2P Tz8r1b8dpwwlQ== From: "Matthieu Baerts (NGI0)" To: mptcp@lists.linux.dev, stable@vger.kernel.org, gregkh@linuxfoundation.org Cc: Paolo Abeni , sashal@kernel.org, Shardul Bankar , Xinyang Ge , "Matthieu Baerts (NGI0)" , Jakub Kicinski Subject: [PATCH 5.15.y 2/2] mptcp: close race between scheduler and state change Date: Sat, 19 Sep 2026 22:29:21 +0200 Message-ID: <20260919202918.2074632-6-matttbe@kernel.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260919202918.2074632-4-matttbe@kernel.org> References: <20260919202918.2074632-4-matttbe@kernel.org> Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1643; i=matttbe@kernel.org; h=from:subject; bh=SM1NCJ+XyNa0LwwgpdEzAq2+G78I5l0TBurls9PYHR0=; b=owGbwMvMwCVWo/Th0Gd3rumMp9WSGLLWfVi4/FfZwye/AlR0imvYThhKad/o9va3s1rJwKNoz pv6eO6SjlIWBjEuBlkxRRbptsj8mc+reEu8/Cxg5rAygQxh4OIUgIkIeDIyHPyZ4qyzOYDho6HV /6pjK2YlLS/c5G/2jc24i70wTt0nk+GffscxkeNuz24f+3tLSWL5mnBpp9iChM53vN43kr6+/Rb DCgA= X-Developer-Key: i=matttbe@kernel.org; a=openpgp; fpr=E8CB85F76877057A6E27F77AF6B7824F4269A073 Content-Transfer-Encoding: 8bit From: Paolo Abeni commit 42064de57fb83231fcc89663a94885f228a1ee53 upstream. The mptcp scheduler may race with subflow sockets state change: data transmission on the selected socket may fail and a later release could try to use mss_now reset to 0 for a divide operation. Address the issue by explicitly checking for the critical scenario. Fixes: c886d70286bf ("mptcp: do not queue data on closed subflows") Cc: stable@vger.kernel.org Reported-by: Shardul Bankar Reported-by: Xinyang Ge Closes: https://lore.kernel.org/20260525194828.1137119-1-shardul.b@mpiricsoftware.com Signed-off-by: Paolo Abeni Reviewed-by: Matthieu Baerts (NGI0) Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260917-net-mptcp-misc-fixes-7-3-rc4-v2-2-0cf5c72667c8@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Matthieu Baerts (NGI0) --- net/mptcp/protocol.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 42190efadb11..2f18dcb8d034 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -1621,7 +1621,9 @@ static struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk) static void mptcp_push_release(struct sock *ssk, struct mptcp_sendmsg_info *info) { - tcp_push(ssk, 0, info->mss_now, tcp_sk(ssk)->nonagle, info->size_goal); + if (info->mss_now) + tcp_push(ssk, 0, info->mss_now, tcp_sk(ssk)->nonagle, + info->size_goal); release_sock(ssk); } -- 2.55.0